A liquid-vapor display

A new reflective display principle is described. A roughened glass surface wetted with a transparent volatile liquid of the same refractive index as the glass acts as a transparent medium. The electrical heating, via transparent electrodes, of a thin film of liquid adjacent to the roughened surface transforms the glass into a light scattering surface. The fundamental thermal, electrical, and optical characteristics of the display element are reported. Schemes are described for building simply constructed flat panel arrays of liquid-vapor display elements. Such displays are capable of gray scale, can be designed to have frame-time or permanent memory, and can be matrix addressed by electronic, thermal, or geometric means.